The use of introducer catheters, balloon catheters and similar devices in cardiology is well known. Often an introducer catheter is used to guide the balloon catheter. The introducer catheter includes a hemostasis valve at its proximal end for preventing blood loss when the introducer catheter is placed in an artery. An example of an improved hemostasis valve is described in U.S. Pat. No. 4,798,594 to Hillstead and is incorporated by reference. Since less blood is lost with the improved hemostasis valve, the need for blood transfusions is reduced and the chances of contracting AIDS, hepatitis and other blood-borne diseases is lessened.
A problem with the new hemostasis valve is in the insertion of the guide wire and balloon catheter through the hemostasis valve without damage to the guide wire or balloon catheter. Cardiologists often will bend the tip of the guide wire and of a balloon catheter to a preselected angle to ease insertions of the balloon catheter into the artery to be opened. When the cardiologist inserts the guide wire and balloon catheter through the hemostasis valve, the bend in the tip of the guide wire may change, making the task of correctly positioning the balloon catheter more difficult, if not impossible.
A catheter insertion device for use with an introducer catheter is described in U.S. Pat. No. 4,569,347 to Frisbie. Frisbie's catheter insertion device utilizes a helically or spirally cut tubular member and a pull member attached to the tubular member. The pull member is provided on one end of the tubular member to facilitate removal of the catheter insertion device from the hemostatic valve of the introducing catheter.
The Frisbie catheter insertion device is inserted through the hemostasis valve with either a mandrel or a dilation catheter inside the insertion device to make the insertion device stiff. If a mandrel is used, the mandrel is withdrawn after the catheter insertion device is inserted through the hemostasis valve. Once the mandrel is removed, the balloon or dilation catheter can be pushed through the catheter insertion device and into the guide catheter. Once the catheter introducing device and dilation catheter is inserted through the hemostasis valve, the catheter insertion device can be separated from the hemostasis valve, unwound and pulled away from the dilation catheter.
Other insertion devices for use with transfusion catheters or cardiac electrodes have been described by Buhler in West German Patent 2,026,572, Kling in U.S. Pat. No. 4,412,832 and Osborne in U.S. Pat. No. 4,306,562.
Buhler describes a dividable, short, plastic catheter that can be produced in an extrusion process. Buhler's catheter uses two polymers, such as polyethylene and polypropylene, that are insoluble with one another. When the catheter is extruded, two lengthwise strips of one polymer displaced by about 180.degree. are embedded into the catheter formed from the other polymer to form two longitudinal lines of weakness. The catheter is described as being used as an auxiliary device for the introduction of a longer, flexible infusion catheter into a patient.
Kling's introducer catheter has longitudinal scored lines of weakness on the catheter tube along which the catheter can be split. Tabs serve as grips which facilitate the splitting of the catheter. The introducer catheter is described as an "over-the-needle" type in which the introducer catheter is telescopically mounted over a hypodermic needle. The needle is removed after insertion of the introducer catheter into the patient and a pliant infusion catheter is introduced through the lumen of the introducer catheter. Once the infusion catheter is in place, the introducer catheter is withdrawn from the patent and then peeled apart from the infusion catheter. A slidable sleeve on Kling's introducer catheter can be sutured to the patent to support the infusion catheter.
Osborne, in U.S. Pat. No. 4,306,562, describes a flexible cannula for use in inserting pacemaker electrodes. The cannula itself is similar to Kling's introducer catheter. One difference between Osborne's cannula and Kling's catheter is that the Osborne cannula does not have a slidable sleeve on the cannula.